OPTICAL COMMUNICATION SYSTEM AND OPTICAL COMMUNICATION METHOD

摘要

PURPOSE:To suppress modulation distortion by measuring a characteristic parameter of a correction light emitting means at any time and updating the operating parameter of a communication system at any time based on the value of the measured characteristic parameter. CONSTITUTION:The optical communication system basically consists of a main semiconductor laser 2 applying directly intensity modulation to an analog signal sent from a signal generator 11 and to be sent into an optical signal, a main optical fiber line 4 sending the optical signal subjected to intensity modulation and a main photodetector 9 demodulating the optical signal subjected to intensity modulation into an electric signal. Then the optical feedforward system is adopted and the input current optical output characteristic of the correction light emission means (sub semiconductor laser) 7 giving the most adverse effect onto the modulation distortion is monitored at any time and feedback control to correct the parameter of the communication system is applied in response to the change in the characteristic. Thus, the effect of the characteristic change of the semiconductor laser due to environmental and secular change is suppressed and the modulation distortion is suppressed.